Quenching from liquid

Consider a polymer is quenched from liquid to glass where the sample is annealed. During isothermal annealing, the number of holes is close to a conserved quantity. The local excess of number density of the quenched glass relaxes by spreading slowly over the entire region, and is governed by... 

Nagakura, S., S. Toyama, and S. Oketani Lattice parameter and structure of Ag—Cu alloys rapidly quenched from liquid state. Acta Met. 14, 73 (1966). 

Mor] SEM, EPMA of alloys quenched from liquid state 1180-1420°C, up to 3 mass% V and up to 4 mass% C, (yFe)/liquid... 

The principle changes that occur on the modified steel surface by the high speed quenching from liquid state in the treatment process can be described as ... 

Au,Cn)3oTe7 (metastable) 0---17at% Cu ) cubic P See Fig. 52a A = l a-Po-type. X, foils. Rapid quenching from liquid state. 67 Tsui... 

In conclusion, the different thermal histories imposed to PTEB have a minor effect on the /3 and y relaxations, while the a. transition is greatly dependent on the annealing of the samples, being considerably more intense and narrower for the specimen freshly quenched from the melt, which exhibits only a liquid crystalline order. The increase of the storage modulus produced by the aging process confirms the dynamic mechanical results obtained for PDEB [24], a polyester of the same series, as well as the micro-hardness increase [22] (a direct consequence of the modulus rise) with the aging time. 

The thickness of amorphous alloys is dependent upon production methods. Rapid quenching from the liquid state, which is the most widely used method, produces generally thin amorphous alloy sheets of 10-30 tm thickness. This has been called melt spinning or the rotating wheel method. Amorphous alloy powder and wire are also produced by modifications of the melt spinning method. The corrosion behaviour of amorphous alloys has been studied mostly using melt-spun specimens. 

Sinha, A. K., Giessen, B. C., and Polk, D. E., Metastable Phases Prodiced by Rapid Quenching from the Vapor and the Liquid. Treatise on Solid State Chemistry, ed. N. B. Hannay. Vol. 3. 1976. 

Considerations about metastable diagrams involving very rapid quenching from the liquid state date back to the work by Duwez (1967). An interesting contribution to this subject is summarized in Fig. 2.36. It shows the equilibrium diagram of the Au-Sb alloys and the sequence of phases observed by fast quenching (Giessen and Willens 1970, Massalski 1989). 

It is important to describe the preparation of these samples, which were annealed at high temperature in dry nitrogen gas and then rapidly quenched in liquid nitrogen. Because they were thereby rendered amorphous, there was no scattering due to the PTFE-like crystallinity that would complicate the data interpretation. Membranes were boiled in NiCL solutions and then soaked in H2O, D2O, and H2O/ D2O = 50 50 solutions. Due to the elimination of crystallinity from the melt-quench pretreatment, these samples were considerably hydrated at 41 vol %. 

Figure 9.3 Energy of a 64 atom supercell of InP during quenching from a liquid state into an amorphous state. The energy of crystalline InP is also shown. (Reprinted by permission from the source cited in Fig. 9.2.)...

Recently, Silver and Bray (52) were able to differentiate and to estimate the relative proportions of three- and four-coordinated borons in binary borate glasses. This technique was thus adopted by the present author in order to ascertain the presence or absence of four-coordinated boron in liquid B203 (35). Glassy samples were quenched in liquid mercury from temperatures up to 1400°C but no four-coordinated boron was detected. (The lower limit of detectability was estimated to be about 2%.) Experiments were also carried out on liquid B203 up to 500°C but again no four-coordinated boron was found. It thus appeared that at least up to 500 or 600°C, the structural variation of liquid B203 with temperature is not primarily the result of a boron coordination change of from three to four. 

Transmission electron micrography has, remarkably, been successfully used to image micelles formed by block copolymers in dilute solutions. Price and coworkers used two preparation methods. In the first method (Price and Woods 1973), f reeze etching, a drop of solution was rapidly frozen by quenching in liquid nitrogen. Solvent was then allowed to evaporate from a freshly microtomed surface of the droplet. Finally, a replica was made of collapsed micelles raised proud from the frozen surface. In the second method (Booth et al. 1978), a drop of micellar solution was allowed to spread and evaporate on a carbon substrate, and 0s04 was used to selectively stain one of the blocks. 

Fig. 2.7 (a) TEM micrograph from an /ps = 0.40, Nn = 209 PS-P2VP diblock, annealed at 140 °C for 6h then quenched in liquid nitrogen. Iodine was used to selectively stain the PVP. (b) SANS pattern from the same phase after preshearing at 140 °C (Schulz et al. 1996). (c) Possible orientations of the lam phase with respect to the shear coordinates. 

The textures in homeotropic lamellar phases of lecithin are studied in lecithin-water phases by polarizing microscopy and in dried phases by electron microscopy. In the former, we observe the La phase (the chains are liquid, the polar heads disordered)—the texture displays classical FriedeVs oily streaks, which we interpret as clusters of parallel dislocations whose core is split in two disclinations of opposite sign, with a transversal instability of the confocal domain type. In the latter case, the nature of the lamellar phase is less understood. However, the elementary defects (negative staining) are quenched from the La phase they are dislocations or Grandjean terraces, where the same transversal instability can occur. We also observed dislocations with an extended core these defects seem typical of the phase in the electron microscope. 

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